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Given that sin x = 1 / sqrt(3) where x is an acute angle, determine the following: i) cos x, ii) cos2(90-x), iii) cot 2x. Starting from a right-angled triangle, determine whether sin x is a... Evaluate the following without use of figures.

Mathematics

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Dennis, hebu tusuluhishe hili.

Tunapewa sin⁡x=15\sin x = \frac{1}{\sqrt{5}} na xx ni pembe kali.

a) (i) Tafuta cos⁡x\cos x

  1. Tumia utambulisho wa Pythagorean sin⁡2x+cos⁡2x=1\sin^2 x + \cos^2 x = 1.

    Badilisha thamani ya sin⁡x\sin x:

    (15)2+cos⁡2x=1\left(\frac{1}{\sqrt{5}}\right)^2 + \cos^2 x = 1 15+cos⁡2x=1\frac{1}{5} + \cos^2 x = 1
  2. Tatua kwa cos⁡2x\cos^2 x.

    cos⁡2x=1−15\cos^2 x = 1 - \frac{1}{5} cos⁡2x=45\cos^2 x = \frac{4}{5}
  3. Tafuta cos⁡x\cos x.

    Kwa kuwa xx ni pembe kali, cos⁡x\cos x itakuwa chanya.

    cos⁡x=45\cos x = \sqrt{\frac{4}{5}} cos⁡x=25\cos x = \frac{2}{\sqrt{5}}

    Ili kurahisisha, zidisha nambari na denominata kwa 5\sqrt{5}:

    cos⁡x=255\cos x = \frac{2\sqrt{5}}{5}

    Jibu la (i) ni 255\boxed{\frac{2\sqrt{5}}{5}}.

    a) (ii) Tafuta cos⁡2(90∘−x)\cos^2 (90^\circ - x)

  4. Tumia utambulisho wa kikoa cos⁡(90∘−x)=sin⁡x\cos(90^\circ - x) = \sin x.

    Hivyo, cos⁡2(90∘−x)=(sin⁡x)2\cos^2 (90^\circ - x) = (\sin x)^2.

  5. Badilisha thamani ya sin⁡x\sin x.

    cos⁡2(90∘−x)=(15)2\cos^2 (90^\circ - x) = \left(\frac{1}{\sqrt{5}}\right)^2 cos⁡2(90∘−x)=15\cos^2 (90^\circ - x) = \frac{1}{5}

    Jibu la (ii) ni 15\boxed{\frac{1}{5}}.

    a) (iii) Tafuta cot⁡2x\cot 2x

  6. Kwanza, tafuta tan⁡x\tan x.

    Tunajua tan⁡x=sin⁡xcos⁡x\tan x = \frac{\sin x}{\cos x}.

    tan⁡x=1525\tan x = \frac{\frac{1}{\sqrt{5}}}{\frac{2}{\sqrt{5}}} tan⁡x=12\tan x = \frac{1}{2}
  7. Tumia fomula ya tan⁡2x\tan 2x

    tan⁡2x=2tan⁡x1−tan⁡2x\tan 2x = \frac{2 \tan x}{1 - \tan^2 x}.
    Badilisha thamani ya tan⁡x\tan x:

    tan⁡2x=2(12)1−(12)2\tan 2x = \frac{2 \left(\frac{1}{2}\right)}{1 - \left(\frac{1}{2}\right)^2} tan⁡2x=11−14\tan 2x = \frac{1}{1 - \frac{1}{4}} tan⁡2x=134\tan 2x = \frac{1}{\frac{3}{4}} tan⁡2x=43\tan 2x = \frac{4}{3}
  8. Tafuta cot⁡2x\cot 2x.

    Tunajua cot⁡2x=1tan⁡2x\cot 2x = \frac{1}{\tan 2x}.

    cot⁡2x=143\cot 2x = \frac{1}{\frac{4}{3}} cot⁡2x=34\cot 2x = \frac{3}{4}

    Jibu la (iii) ni 34\boxed{\frac{3}{4}}.

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